Set-top box: Meaning (information, definition, explanation, facts)

The term set-top box describes a device that connects to a television and some external source of signal, and turns the signal into content then displayed on the screen. The signal source might be a satellite dish, a cable (see cable television), a telephone line, a DSL connection, or even an ordinary VHF or UHF antenna. Content, in this context, could mean any or all of video, audio, Internet webpages, interactive games, or other possibilities.

Before cable-ready TV sets, a set-top box was used to receive analog cable TV channels and convert them to one that could be seen on a regular TV (channel 3 or 4 in North America). A digital set-top box is needed for receiving digital TV broadcasts, because the vast majority of TV sets do not yet have such a tuner. In the case of direct broadcast satellite (mini-dish) systems such as SES Astra or DirecTV, the set-top box is an integrated receiver/decoder (IRD).